This invention relates generally to a method and apparatus for detecting the movement and identification of an article. More particularly, the invention relates to a method and apparatus for detecting unauthorized movement and subsequent identification of an article by employing a plurality of radioactive isotopes disposed on or within the article.
Security and internal control systems for certain articles including, but not limited to, electronic and mechanical devices, documents, precious metals, oil and the like, are very limited in their effectiveness. Traditional alarm detectors used to monitor a given situation and provide the information required are typically inapplicable to the control and security of devices such as those recited above.
For example, conventional burglar alarms employ a metallic tape placed around windows and switches on doors. These devices have an electric current passing through them which actuates an alarm when interrupted. Devices of this nature are intended to prevent unauthorized entrance into buildings. Consider, however, a situation where an employee or customer who has authorization to enter the building seeks to remove articles therefrom without approval. An ordinary burglar alarm system will only detect the unauthorized entrance into a building and does not monitor or detect movement of individual articles within that building. As recited above, this system does not detect the movement of an article without the owner's permission.
A conventional theft detection system which employs electronic transmitters and receivers to detect unauthorized movement is disclosed in U.S. Pat. No. 4,274,090, dated June 16, 1981, to Cooper. This system is readily defeated by placing a minimal amount of thin, lightweight shielding material around the protection device, and hence offers limited protection. Additionally, the protection device is readily visible to the eye; sufficiently bulky as to encumber the appearance, handling and function; and/or induces an electronic interference in many articles such as commonly found in semiconductor devices.
Beyond detecting unauthorized movement of articles, another area of interest is the ability to identify and authenticate a true article from a bogus or counterfeit one. For example, the semiconductor industry has a serious problem with rejected and scrapped articles appearing in the marketplace. It is possible to obtain these rejected articles and apply a semiconductor company's name, logo, numbering system, etc. and misrepresent the articles as the ones of value. These bogus or counterfeit articles are impossible to tell from true ones without extensive electronic test equipment. Thus for many articles and specifically those listed above, not only is unauthorized movement arduous to detect, but identifying and authenticating the article is difficult.
Accordingly, it is desirable to provide a method and apparatus for detecting unauthorized movement of an article, as well as providing a means and method for identifying and authenticating same. It would be a further advancement to achieve the preceding as well as pinpointing the date of manufacture of the article. Of particular significance is to achieve the above for either very small articles, or those having high monetary value. Additionally, it would be an advancement to detect unauthorized movement of articles without employing bulky electronic devices which can readily be rendered ineffective by employing a minimum amount of thin, lightweight shielding material.